US Airdate : 6 October 2003
UK Airdate : 8 June 2004

Based on a tip from Lexa’s (Karen Cliche) contacts, Brennan (Victor Webster) and Shalimar (Victoria Pratt) wait in an alley where a new genetically engineered weapon is supposed to be exchanged. A car suddenly pulls up and a man gets out and places something small next to a dumpster. As he drives off, Jesse (Forbes March) traces the license plate to the Westland Casino. Moments later, Carlos “The Tiger” Lavista (Michael Miranda) and his bodyguard enter the alley and pick up the package, which is an aerosol container. Without notice, Carlos hits his guard in the stomach and sprays the contents of the container into his face. Within seconds, the man drops to the ground, begins violently convulsing and dies. Brennan and Shalimar go after Carlos and when Shalimar kicks him to the ground, he drops the container and a hotel key. Carlos then throws a knife at Brennan which Shalimar catches just as Carlos escapes.

At Sanctuary, Jesse reveals that the aerosol can contained a prion, a poison made of a modified protein molecule that converts normal proteins and kills those infected. Suspecting Kristen Greg (Deborah Odell), the Westland Casino owner, is involved in selling the prion, Lexa suggests Brennan and Shalimar go to the casino to investigate. At the casino, Shalimar watches Kristen from the bar. When a man sits next to Shalimar, Jesse uses a video feed to identify him as known terrorist Eduardo Cruz (Jeff Camson). Noticing the man has a mysterious gold chip, Shalimar asks if she can join him while Jesse monitors the crowd and sees a number of other terrorists, all of whom he believes are there for the prion. Brennan, wanting to get closer to Kristen, draws her attention by using his powers to win a great deal of money at a roulette table. Meanwhile, Lexa uses the key Carlos dropped to enter his hotel room. She shoots a laser beam from her hand to melt the lock on the room’s safe where she finds an assortment of passports and a gold chip, which she pockets. Carlos suddenly appears and holds a gun to her neck, but she slaps the gun out of his hand and knocks him over the balcony with a flying kick. When she runs to the railing to make sure he’s dead, she realizes he’s gone.

Back at Sanctuary, Jesse tells the team that the gold chip Lexa retrieved is filled with electronics and encrypted with an I.D. He also reveals that Kristen has a few ex-GSA members on her payroll. When he shows them photos of the people, Lexa reacts strongly to one of the pictures and walks out. Jesse suggests Shalimar put a device on one of Kristen’s computers in order to locate the prion so they can switch it for a harmless substitute. Meanwhile, Lexa contacts a mysterious man on her computer and asks to be set up with a new I.D. so she can get to Kristen, who she believes is the link to Dominique, a woman she’s been searching for. At the casino, Brennan is having a drink with Kristen when he notices Lexa across the room.

After saying goodbye to Kristen, Brennan approaches Lexa who tells him that he and Shalimar are off the case. She then kisses Brennan and tells him to stay out of her way before walking off.Using her new I.D., Lexa convinces Kristen to let her attend an auction she is holding later that night. Meanwhile Jesse tells Brennan and Shalimar that Lexa’s sudden actions may be linked to a woman named Dominique who was in one of the photos of ex-GSA members he had shown them earlier. Brennan tells Jesse to research Dominique while he heads back to the casino.

At the casino, Brennan finds Kristen and suggests they go somewhere private. She takes him to her office and leads him into a posh back room. Shalimar then sneaks into Kristen’s office and attaches a device Jesse gave her to a computer, allowing Jesse to monitor the casino from Sanctuary. An enraged Lexa suddenly appears and the two are about to fight when Shalimar senses someone approaching and runs out of the office. A moment later, one of Kristen’s employees, Carter (Noah Danby), enters and hits her with a psionic blast, freezing her in place. In the back room, Kristen tells Brennan she feels like he’s playing a game with her. He placates her with a soft kiss. Meanwhile, Shalimar comes to Lexa’s rescue, knocking Carter out with a series of kicks and punches. Having heard the commotion, Kristen breaks the kiss with Brennan opens the door to her office just as Shalimar pulls Lexa and an unconscious Carter under a table to hide. Kristen walks right for them, but Lexa refracts the light around them and they all disappear. Finding no one there, Kristen returns to Brennan. As the two engage in another kiss, Kristen gently pushes him away and excuses herself for a moment. She goes back into her office and makes a call to check out the name Allen Dawson -- Brennan’s alias. Meanwhile, Jesse tells Shalimar that the container they’re looking for is in a vault in the basement and that she’ll need Brennan’s help to replace it with the substitute container. Kristen walks back towards Brennan with a pistol aimed at him and tells him she knows he’s not Allen Dawson.

Brennan calmly tells Kristen he’s known as “The Tiger” and takes the gold chip from his jacket pocket. He says he didn’t reveal his true identity to her as he was ambushed when he picked up the sample and wasn’t sure if he could trust her. Still skeptical, Kristen lowers the gun and tells him the auction is in her office in an hour. Brennan leaves the office and contacts Jesse who informs him that the mutant that attacked Shalimar and Lexa has a fixed genetic code that has stabilized his mutations. Brennan insists it’s not possible as Adam failed many times trying to stabilize their mutations. Jesse suggests that Dominique may have figured out how to accomplish this, and assumes that’s why Lexa is looking for her. Seeing Lexa, Brennan rushes over and confronts her. Lexa is shocked when he asks about Dominique, but she refuses to offer any information. In the basement, Shalimar makes her way through the vault’s security system with Jesse’s help and goes inside. Meanwhile at the auction, Brennan’s cover is blown when Carlos “The Tiger” shows up. Brennan tries to escape, but Kristen’s feral mutants pin him down.

Inside the vault, Shalimar is caught off-guard when the lasers suddenly turn off and she hears someone approaching. A feral mutant enters the room and the two engage in a fight causing the two identical containers to fall to the floor. Shalimar knocks the mutant out, grabs one of the containers and flees.

Meanwhile, Kristen tells her bodyguard to find out who Brennan really is and then kill him, but Lexa suddenly blasts the guard with a beam of concentrated light and she and Brennan race out the door. As they race down the corridor, Brennan fires tesla coils at their pursuers. Shalimar meets up with them and begins to show them the way out, but Kristen’s guards use gunfire to push them into the vault. Having just completed her business with Carlos, Kristen hits a key on the computer to close the vault door and tells Brennan, Shalimar and Lexa through a speaker that she’s arranged for a demonstration of the biological weapon. Shalimar assures her teammates that she grabbed the prion container from the vault, just as a mist enters the room. Kristen watches as Mutant X falls to the ground one by one, but Carlos quickly notices that Lexa has disappeared and the guards enter to investigate. Lexa reappears and blasts the guards with a bright flash of light. Returning to Sanctuary, Jesse asks Lexa about Dominique and she tells him it is believed Dominique knows more about genetic engineering than anyone and that she may be able to help a man Lexa is looking for. Meanwhile, Kristen is on the phone with Dominique, apologizing for the theft of the weapon. When they hang up, Dominique tells one of her men to find out who stole the weapon so they can prevent any further interference.